磁头气膜浮动块浮动特性的影响因素

近年来,随着创新性技术的不断应用,硬盘驱动器的气膜浮动块(以下简称浮动块)也有了较大改进,例如浮动块表面的设计越来越精巧,而性能却更加稳定。因此很好的理解哪些因素是影响气膜浮动块浮动特性的主要原因显得尤为重要。分析这些因素对浮动块的影响结果,有利于我们改进浮动块的特性并对其发展前景做出预测,本文对这些影响因素做了概括总结。     

轻负荷磁头的气动特性

本文采用数值方法求解修正雷诺方程,给出轻负荷、小间隙浮动块的气膜压强分布,飞升曲线以及浮动块几何尺寸、负荷、重心位置的误差对磁头气动特性的影响等结果。     

浮动磁头浮动特性分析

1.前言本文以小型磁盘装置JK-811的圆形浮动块为例,用数值计算方法,对浮动块的静态特性进行了分析。分析中,假定空气是可压缩流体,空气的惯性力可以忽略不计,以及空气膜厚度具有弯曲的表面和有限的宽度。影响浮动状态的各因素有:浮动块的外形、浮动块支撑机构、浮动块负荷机构、浮动块表面状态、盘表面的振动以及使用环境。设计浮动块时须注意:1)加强浮动块和磁盘之间流动的气垫的刚性,以提高固有的振动频率;2)提高空气     

TRC磁头浮动块公差敏感性问题研究

采用数值法研究了ＴＰＣ磁头浮动块的公差敏感性问题。首先给出数值模拟公式，然后对一种ＴＰＣ磁头浮动块进行数值优化，研究此浮动块对加工工艺公差的敏感性。加工工艺公差主要包括台阶偏心公差、刻蚀深度公差、球冠面的Ｃｒｏｗｎ和Ｃａｍｂｅｒ。给出了影响浮动特性诸多参数的公差表，并对综合影响作了研究。     

用模块化方法(BBA)分析飞行磁头浮动块机构的亚微米浮动间隙的动态特性

本文用模块化方法(BBA)来叙述由悬挂万向支架弹簧机构、驱动臂机构及空气轴承浮动块组成的总的飞行磁头浮动块机构的亚微米浮动间隙的动态特性。基于模态综合方法及有限元方法基础上的BBA适用于由流体润滑膜系统及结构机构系统组成的系统。悬挂万向支架弹簧及驱动臂作为一个三维分布质量系统影响到浮动块的动态特性,以及除了空气膜谐振外,由悬挂万向支架弹簧机构与驱动臂机构引起的谐振或非谐振存在于浮动块的频率响应中。对于上述这些现象已成为清楚的了。而且,从浮动块动态特性的观点来比较温彻斯特(Winchester)机构及惠特尼(Whitney)机构,并获得这两种悬挂机构的允许的介质加速度值,进行了理论值与实验结果的比较。比较结果表明:两者很好地吻合,而且,BBA计算机模拟被证实是对整套飞行磁头机构进行动态特性分析的正确的及高效的方法。     

磁头浮动块在浮动过程中的磨损

温式磁盘驱动器中的三轨式铁氧体磁头浮动块是以接触启停方式浮动的。本文分析了该磁头浮动块在其整个浮动过程——边界润滑浮动、混合润滑浮动和完全动压润滑浮动中的磨损情况,并且对嵌入磁盘内的浮动块磨损微粒进行了数量分析。结果表明,当磁盘速度大于20m/s时,完全动压浮动中的磁头浮动块的磨损大大减少并趋于零;正常设计的磁头浮动块在以接触启停浮动方式的整个浮动过程中磨损微小,对正常工作无影响。     

磁头浮动块润滑导轨球冠面对磁头浮动特性的影响

本文首先导出磁头浮动块润滑导轨球冠面ＣＲＯＷＮ与ＣＡＭＢＥＲ的近似关系，然后分别研究了ＣＲＯＷＮ与ＣＡＭＢＥＲ对普通楔平面磁头浮动特性的影响。及ＣＲＯＷＮ和ＣＡＭＢＥＲ的综合影响，同时也研究了润滑导轨球冠面对等飞高磁头寻道定位过程浮动特性的影响．     

磁头浮动块动态浮动特性分析

本文通过采用有限差分法求解修正的非定常的雷诺方程，并采用四阶龙格－库塔法求解飞行磁头的动力学方程组，分别计算了常规的Ｔ－Ｆ浮动块和带减压槽的Ｔ－Ｆ浮动块飞的肋面各种障碍物时的动态响应特性，并将两者进行了对比分析，讨论了其动态性能的优劣，计算结果与文献给出的实验结果相符合得较好。     

磁头浮动特性研究——动态分析

本文对流体润滑方程和浮动块动力学方程进行了耦合时域动态求解。结合实际磁盘机中的一种两轨式磁头浮动块,对浮动块的各项动态性能作了分析。仿真了磁头浮动块飞越各种盘片障碍物时的飞行姿态和浮动块对盘片波动的响应。通过对冲击响应进行FFT变换求取了空气支撑的频率结构。     

压电致动式磁头加/卸载机构及其在硬盘驱动器抗冲击中的应用

本文介绍小型大容量硬盘驱动器中采用的一种压电致动式磁头浮动块加／卸载机构。根据机构的工作机理对浮动快加我时的加载速度和浮动块的初始姿态角对头盘接触的影响进行的分析研究。介绍了确保头上不接触碰撞的有关参数，提出了利用该机构实现小型硬盘驱动器抗冲击主动控制的方法。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate